This effectively shuts down expansion of the reservoir for at least one more year. The EPA accused the town of violating the 1972 Clean Water Act by destroying at least 12 acres of federally protected wetlands when a town contractor dumped dirt on the area without a permit while expanding for future water storage.

The EPA ordered Erie to return the reservoir to its natural state. Erie officials are refusing, saying they didn't do anything wrong.

Erie also argued that a Supreme Court decision in January in an Illinois case limited the scope of the Clean Water Act. Town officials said that ruling should be applied to Prince One as well.

In the Illinois case, justices ruled that seasonal wetlands are not protected by the Clean Water Act. They said the act is intended to cover major rivers or drainage systems flowing from state to state.

Erie lawyers said Prince One should not be protected by the EPA because it is seasonal, filling with water only in the spring, and is fed by an irrigation ditch not a river.

U.S. Department of Justice attorney Allen Greenburg disputed that, saying the reservoir is fed by the South Boulder Canyon Ditch, which connects to Coal Creek, which connects to Boulder Creek, which connects to the South Platte River, which flows state to state.

David Getches, a University of Colorado law professor and water-law specialist, said the Clean Water Act does apply to Prince One. He said the wetlands in the Illinois case did not connect to a major river and that makes those wetlands different from Prince One.